About the Author Gary B. Xavier is a Stationary Engineer with nearly 50 year’s experience in the HVACR fi eld. He began working with refrigeration equipment as a teenager, eventually starting a service company that dealt with the waterside service of large boilers and cooling systems. Gary is licensed to work in both New York and Pennsylvania. He is the author of over a dozen technical training books and slide presentations used to train engineers and technicians throughout the US and Canada. He has also published numerous technical trade magazine articles. An instructor for the past 20 years, Gary currently conducts training seminars as well as providing consulting services on HVACR and boiler systems. His clients include the United States Department of State, Department of Defense, Bureau of Prisons, U.S. Army, U.S. Navy, Ford, General Motors, Boeing, Pepsi, several major pharmaceutical manufacturers, and both fossil-fuel and nuclear power plants. He is a member of the American Society of Heating, Refrigerating, and Air- Conditioning Engineers (ASHRAE), the Refrigerating Engineers and Technicians Association (RETA), and the National Association of Power Engineers (N.A.P.E.). Reviewers The author and publisher wish to thank the industry and teaching professionals listed below for their valuable input into the development of Math for HVACR. Anthony Saccavino Porter and Chester Institute Watertown, Connecticut Mike Jonas Morton College Cicero, Illinois